Vultr supports FreeBSD and gives us both a single ipv4 and a range of ipv6 addresses. So the simple thing to do is to give each container its own public ipv6 address. No need to mess with vnet. At least that is the theory. Wish me luck in getting this working. Am I really the first person to be using this approach?
I hope I got this all correct. I did get the containers networked correctly on vultr, but I am not a networking guy so I hope I did not misstate anything. Any edits I am happy to fix. And now I have to run, I am late for the multi lingual meetup. But this stuff is way more fun.